Aldehydo-carboxylic acid



Patented Feb. 22, 1944 2.342.007 ALnEnYno-clmnomc ACID Herman A. Brnson and Thomas W. Biener, Philadelphia, Pa., assignors to The Resinous Prodacts a Chemical Company, Philadelphia, Pa., a

corporation of Delaware No Drawing. Application March 16, 1943, Serial No. 479,338

5 Claims. (01. 260-526) This invention relates to new aldehydo carboxylic acids having the general formula wherein R and R are each monovalent hydrocarbon groups.

We have found that aldehydo carboxylic acids of the above structure may be obtained by hydrolyzing the corresponding cyano tertiary aldehydes with aqueous solutions of alkalies or inorganic acids.

Although it is known that the --C =.N group of lower nitriles may be hydrated in the presence oi alkali or acid and the resulting product split.

higher or complex nitriles are not in general read-' tion in their presence. In contrast to the accepted facts concerning nitrile and aldehydo groups, the

cyano tertiary aldehydes give high yields of pure tertiary aldehydo acids without appreciable loss through the usual reaction involving aldehydes and alkalies or acids.

This behavior of the cyano aldehydes is all the more remarkable in view 01 the fact that the aidehydo group in the new aldehydo acids retains its capacity to undergo typical reactions of aldehydes, such as reactions with hydrogen, hydrogen cyanide, hydroxyl-amine, phenylhydrazine, urea, melamine, dicyandiamide, primary amines. ammonia, or hydrogen sulfide. Likewise. it has been found that the aldehydo group in the new acids reacts with compounds having a reactive methylene group between two ethencid carbon atoms in a carbocycle such as in indene, fluorene, or cyclopentadiene. Similarly, the tertiary aldehydes of this invention condense with ketones, aldehydes, or nitro-paramns having active methyl or methylene groups contiguous to the multiplebonded functional group. carbonyl or nitro, as the case may be. The aldehydo group may be oxidized to form dibasic acids or reduced to form alcohols which at once form lactones.

The tertiary aldehydo nitriles used as starting materials are new compounds obtainable by reacting aerylonitrile in the presence of an alkaline condensing agent with .disubstituted acetaldehydes as described in our copending application Serial No. 466,050, filed November 18, 1942.

In this copending application it is shown'that in the presence of such alkaline condensing agents as hydroxides, oxides, amides, or hydrides oi the alkali metals, lithium, potassium, sodium, etc. or in the presence of these metals themselves, or in the presence of quaternary ammonium hydroxides including benzyl trimethyl, dibenzyl dimethyl, benzyl triethyl, or other quaternary ammonium hydroxide, there is a reaction between aldehydes and acrylonitrile yielding beta-eyanoethylated products. The aldehydes having the structure R(R')CH-CHO are of considerable importance. particularly when R and R are monovalent allphatic hydrocarbon radicals. Typical disubstituted aldehydes which may be used are the di methyl, methyl ethyl, diethyl, ethyl propyl, ethyl isopropyl, ethyl butyl, methyl butyl, methyl hexyl, methyl octyl, methyl dodecyl or octadecyl, dipropyl, diphenyl, ditolyl, methyl phenyl, methyl tert.-butylphenyl, and methyl benzyl acetaldeydes. Similar aldehydes having unsaturated aliphatic groups may likewise be used. The same end effect is obtained by using substituted acroleins, which, we have now established, undergo a'rearrangement in the presence of an alkaline catalyst. For example, there may be used as starting materials tiglic aldehyde, or alphamethyl-beta-ethyl acrolein, alpha-ethyl-betapropyl acrolein, or other similar aldehyde. Upon reaction with acrylonltrile in the presence of an alkalin condensing agent these aldehydes form derivatives which are cyanoethylated in the alpha-position as the result of shifting of a hydrogen atom and of the double bond. Thus, there results from the above aldehydes the following compounds:

CHzCHzCN CHFOH- -cno CHICHICN oH.cH=cH- 0110 CHICHiCN cmcn=cn=cn- CH0 These can be converted to the corresponding un- 2 aasaeo'r tions as to concentration of hydrolysing agents and temperatures. In general at least one moi of such agent per mol of cyanoaldehyde should be used to ensure complete conversion. Excess is obviously helpful in driving the reaction to 5 completion. Remova1 of ammonia by boiling under normal or reduced pressures also helps to complete the hydration and splitting necessary to yield the carboxylic form. Concentrations of a strong alkali, such as sodium or potassium hydroxide, may vary from about 2% to 25%. Temperatures may vary from about 65 to about 125 0. During the reaction substitutedhydrogenation pyridones may be formed and it is necessary to continue the reaction for a sufii- 5,

cient length of time to break these down into the carboxylic form. when the hydrolysis has been carried to practical completion, the reaction mixture may be treated in conventional ways to liberate the aldehydo acid.

The following examples illustrate this invention, the parts being by weight.

Esmmple 1 To a stirred mixture of 200 pats of diethyl acetaldehyde and 10 parts of methanolic potassium hydroxide solution, there was gradually added 106 parts oi acrylonitriie at 30-35 C. while the reaction mixture was cooled. The temperature rose to about 50 C. after all the reactants had been combined. The reaction mixture was then stirred for two hours after which time no further heat was evolved. The mixture was thereupon acidified with dilute hydrochloric acid,

washed several times with warm water, dried, and 35,

distilled in vacuo. The product obtained had the formula:

01H 0 cn-rLcmdmcn all:

and distilled at 115'-130 C. 5 mm. as a colorless oil in a yield of about 200 parts.

This was hydrolyzed by boiling 153 parts of it with a solution of 50 parts of sodium hydroxide and 500 parts of water while the mixture was.v stirred under reflux. After one and one-half hours of boiling all of the oil consisting of alpha- (Z-cyano-ethyl) -alpha-ethyl butyraldehyde had dissolved. The mixture was acidified with hydro- It distilled at 145-150 C./5 mm. as a colorless oil in a yield of 130 parts. Upon redistillation it' boiled at 140-145 C./3 mm. Upon oxidation with air, alkaline hydrogen peroxide, potassium permanganate or sodium hypochlorite, it yields the,

corresponding alpha, alpha-diethyl-glutaric acid.

which is a new compound consisting of colorless needles melting at 84 C.

Example 2 To a stirred mixture of 126 parts orz-etnyi-s- 7o propylacrolein, 128 parts of tertiary butyl alcohol, and 5 parts of methanolic 30% potassium hydroxide there was gradually added 53 parts of aorylonitrile at 25-35' C. The mixture was stirred hydrochloric acid. washed with water. dried, and distilled in vacuo. The product. having the formuia can oao-d-cmomon n-om-omom distilled at 140-145 C./6 mm. in a yield of Parts.

This was saponified by boiling with a solution of 30 parts of sodium hydroxide and 300 parts of water for five hours under reflux. The product separated as an oil when the solution was treated with hydrochloric acid. The oil was washed, dried, and distilled in vacuo. The product having the formula distilled at 160-170 C./5 mm. as a pale yellow oil in a yield of 50 parts. Upon redistillation it boiledat 153'-l56' C./4 mm.

Example 3 To a stirred solution of 505 parts of ethylbutyl-acetaldehyde, 300 parts of tertiary butyl alcohol, and 40 parts of methanolic 80% potassium hydroxide solution there was added dropwise 265 parts of acrylonitriie during the course of one and one-quarter hours while the reaction temperature was maintained at 3545 C. The mixture was stirred for an additional four hours at room temperature, then acidified with dilute hydrochloric acid resulting in separation of an oil which was washed with water. The oil was separated, dried. and distilled in vacuo. The product having the formula Calls 0 CE--CHIOHION sHl distilled at -150' C./6 mm. as a colorless oil in a yield of 370 parts. Upon redistillation it boiled at -150' C./'1 mm.

A mixture of 30 parts of the above cyanoaldehyde, 15 parts of potassium hydroxide. and 125 parts of water was boiled under refiux for five hours. The product was acidified with dilute hydrochloric acid with precipitation of an oil which was washed, dried, and distilled in vacuo. The product having the formula sHs OKCJJCHsCH:COOH

s-CHsCHsCHs distilled at 180-l68' C./4 mm. as a colorless oil in a yield of 25 parts. Upon redistillation it boiled at 155-l60 C./4 mm. Upon oxidation it yields alpha-ethyl-alpha-butyl-glutaric acid, which is a new compound consisting of colorless needlesmelting at 8l-82 C.

By generally the same procedure as shown above. the cyanoethylation product of' methylhexyl-acetaldehyde yields, upon saponification with aqueous sodium hydroxide, potassium hydroxide, or hydrochloric acid, the correspondin aldehyde-acid CH: onc-d-omomc00H as a colorless high boiling oil.

thereafter for two hours, then acidified with dilute 75 The above-described reactions are applicable to cyanoethylated saturated or unsaturated diwherein R and R are monovaient aliphatic hr substituted acetaidehydes drocarbon groups.

R 3. As a new compound. the tertiary aldehydo & acid having the formula 5 gm. in which R and R. are in particular straight one- TCH'CHCOOH chained or branched chain monovalent hydrocarbon groups. 4. A; a new compotmd. the tertiary aldehyde The tertiary aldehyde acids, their salts and 10 acid having the formula esters are useful intermediates for the preparation of drugs, synthetic fibres, plastics, resins,

plasticizers and perfumes.

We claim: dmcmcmcm As a new compo n a tertiary fl- 15 5. As a new compound, the tertiary aldehyde id vin the formula acid having the formula R CsHl onc ':-cmcmco0n onc-b-cmcmcoon 20 H=CHCH:CH:

wherein R and R are monovaient hydrocarbon groups. HERMAN A. BRUSON. 2. As a new compound, a tertiary aldehydomoms m acid having the formula 5 R OHC-(B-ClIsOHICOOH 

